1. Technical Field
The present invention relates to photonic chips in general, and in particular to a method for polishing photonic chips.
2. Description of Related Art
Conventional photonic chips are typically made from silicon wafers. Silicon wafers tend to be comparatively large, but many photonic chips are required to be in relatively smaller sizes. In order to reach the desired size, the edges of silicon wafers must be cut typically with a diamond tipped saw. However, cutting with a diamond tipped saw will leave silicon wafers with rough or jagged edges, and rough edges are not ideal for optical transmissions. Thus, rough edges need to be polished in order to ensure low-loss coupling to external optical fibers, especially for photonic chips that utilize waveguides extending to the edge of the photonic chips.
Conventional polishing methods suffer in that the polishing of many photonic chips at the same time requires the use of a chip polishing jig that holds the photonic chips perpendicular to a polish platen, and such arrangement does not permit the top edges of the photonic chips to be viewed by an operator. Since the operator cannot see the top of a photonic chip, it is impossible for the operator to determine how deep into the photonic chip that the polish has removed without taking the photonic chip off from the chip polishing jig. Needless to say, additional time is required for the operator to un-mount and remount the photonic chip, which leads to an increase in operational time and a decrease in operational efficiency.
Consequently, it would be desirable to provide an improved method for polishing photonic chips.